Compilare: user.cpp: In function ‘void back(int, int)’: user.cpp:26:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] { for(int r=0; r<L[i].size(); ++r) ^ user.cpp: In function ‘int main()’: user.cpp:49:24: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=] printf("%ld\n",smin); ^ user.cpp:34:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("suma3.in","r",stdin); freopen("suma3.out","w",stdout); ^ user.cpp:34:67: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("suma3.in","r",stdin); freopen("suma3.out","w",stdout); ^ user.cpp:36:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^ user.cpp:37:59: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=0;i<a;i++) for(j=0;j<b;j++) scanf("%d",&v[i][j]);; ^